if i type in @kick Steam_Name it just says sourcemod kicked Steam Name for "Whatever I want"

That's because it's you kicking them. If I kicked someone it would say in your feed: [pF]Surprise [Team Buttsechs] kicked "steam name". In mine, it would say the same message you're seeing. If you're worried if it's working or not, open console and check that the person was indeed kicked.